Tuan Anh Nguyen, 45, injects a syringe filled with heroin in his rented room in Hanoi November 23, 2011. Tuan Anh began abusing drugs 23 years ago after being released from prison. He has since spent most of his life in prisons and rehabilitation centres. Tuan Anh earns a living by running an illegal tea stall that generates $3 to $5 of income daily.
Nguyen Huy Kham/Reuters

A new memory trick may prevent many recovering addicts from relapsing, according to a new study.

Scientists say that because traditional treatment for drug addicts, largely centered around so-called “extinction procedures” designed to sever memories tied with taking drugs to help patients control their cravings, often fail to work and recovering addicts usually relapsed after seeing objects associated with drug-taking like a needle or cigarette.

Some of the existing therapies try to help addicts unlearn their addiction and habit with techniques like showing them videos of people injecting and making them handle syringes while not under the influence. While these techniques reduce cravings at clinics, they are unsustainable after addicts return to their usual surroundings.

Because traditional treatment often fails, clinicians resort to drug related therapies that often have unpleasant side effects, to help reduce associative memories.

The study, published April 13 in the journal Science, showed that it is possible to decrease the likelihood of relapse by rewriting memories associated with triggers that cause cravings, thereby eliminating reactions and the cravings that result for up to six months.

Lin Lu of the National Institute of Drug Dependence at Peking University in Beijing and his research team combined the traditional extinction procedures with a process called memory reconsolidation.

Researchers explained that during consolidations, information, which is retrieved from long-term memory storage, becomes stronger when reactivated. However information becomes temporarily unstable and therefore easy to alter for a short period of time after retrieval.

Lu and his team applied the concept to drug memories by first teaching rats how to self-administer cocaine and heroin so that the animals learned to associated a particular environment with a drug high. Afterwards scientists put the laboratory rats in the same environment, but without drugs.

The findings show that rats showed the least drug-seeking behavior when they were put in the drug-taking environment for 15 minutes, removed from it for 10 minutes and then put back into the environment for 3 hours.

Lin and his team then applied the same type of exercise to actual heroin addicts, by showing patients a 5-minute video of images of heroin use and other activities that often trigger relapse, either 10 minutes or 6 hours before administering the traditional hour-long extinction session, in which they were repeatedly exposed to the same images.

The findings show that those who had been shown the video 10 minutes before the extinction procedures exhibited less reaction to triggers both during the session and up to 180 days later, according to researchers. There was, however, no significant effect of craving in those who watched the video 6 hours before the session.

"The [memory] procedure decreased cue-induced drug craving and perhaps could reduce the likelihood of cue-induced relapse during prolonged abstinence periods," the authors wrote.

Researchers suggest that an explanation for the findings could be that brief exposure before drug-taking memory reactivation made the link between triggers of drug taking and getting high easier to be erased and replaced with a memory in which no such link exists.

Dr. Amy Milton, who researches memory and addiction at the University of Cambridge, told the BBC that the research was “very exciting” because it should that “such a minor" difference from current therapies could tap into an entirely different memory process and reconstruct the original memory.

“Full clinical studies are needed, but it could be really important for treatment of addiction,” Milton told BBC. “There is no theoretical reason it couldn't apply to other addictions such as alcohol. That's obviously very exciting.”